The Science of "Mom Brain"

The research behind a mom's favorite excuse.

If you’re a mom, chances are you’ve heard of “mom brain,” and maybe you’ve even blamed it for a lapse in judgment, a missed appointment, or a minor emotional breakdown at some point in your life. As the mother of a toddler and a newborn, it feels like “mom brain” is the new normal for me. I am forgetful, absent-minded, and am apt to get incredibly emotional if I see so much as a hallmark commercial that features a child within a few years of my son’s age. Watching movies that have anything to do with a child getting lost or hurt is out of the question, and any news footage of children suffering can send me into an emotional tailspin.

Source: Tina Franklin/Flickr

Some people are just sensitive, and maybe this doesn’t sound like anything out of the ordinary. But for me, this kind of forgetfulness and extreme emotionality is out of character: I’m not a crier, and was never really moved before by pictures of babies; I’m generally pretty on top of things, I never miss a deadline, am organized, and even tempered. That is, I was until my son was born 3 years ago. Since then, I have trouble remembering anything that I don’t write down, I experience mood swings, especially when my son is involved, and what’s worse is that these behaviors have become commonplace, especially after I became pregnant again. So what’s my deal? Is “mom brain” just an excuse I use when I’m a mess, or does becoming a mother really affect our brains?

Well, I’m sure it’s true that I use “mom brain” as an excuse for my mistakes from time to time, but it’s also true that our brains are affected by having children, sometimes in ways that are long-lasting. In fact, recent research suggests that a woman’s brain actually changes after she gives birth for the first time, in ways that might promote caring for her child. Researchers from Autonomous University of Barcelona scanned the brains of a group of women before and after they gave birth, and found changes in the structure of their brains that were long lasting, remaining for at least 2 years. Importantly, these changes were particular to the parts of the brain that were most active when the women were looking at pictures of their babies. Although further research is necessary to nail down exactly what these changes mean and how they affect mothers’ behavior, the researchers think these changes might help women understand the needs and emotions of their babies, helping them to better prepare for motherhood (Hoekzema et al., 2016).

Such changes in the way our brains function as a result of becoming a parent don’t just affect new mothers; there is evidence that the brains of fathers are affected as well. In one study, researchers scanned the brains of first-time mothers and fathers while these new parents watched a video of themselves interacting with their babies. The researchers found increased activity in the amygdala—the part of the brain that is responsible for emotional processing—in both mothers and fathers who were the primary caregivers for their babies. In fact, the more involved the fathers were in taking care of their infants, the more their amygdala activity looked like mothers’. This suggests that there isn’t just something special about physically experiencing pregnancy and childbirth that changes how the brain responds to babies (although there are some changes that are mother-specific); the act of parenting itself can also cause similar changes in fathers, or perhaps anyone that plays a large role in raising children (Abraham, Hendler, Shapira-Lichter, Kanat-Maymon, Zagoory-Sharon, & Feldman, 2014).

Researchers have long-suggested that these changes are good ones; they promote sensitivity to a baby’s needs, making us more responsive parents. Unfortunately, these responses could have some negative side effects, perhaps explaining why I (and many new mothers) feel overly emotional from time to time, especially when thinking about the wellbeing of our own children. In fact, our brains' responses to our own children can be quite intense, and some researchers have even compared it to how we experience romantic love (Bartels & Zeki, 2004).

There is also evidence that supports the idea that having a baby interferes with our memory, but not in the way you might think. Researchers speculate that oxytocin—a hormone present in mothers during labor, pregnancy, and nursing—might play a role in keeping women from developing bad memories about the experience (Heinrichs, Meinlschmidt, Wippich, Ehlert, & Hellhammer, 2004). In other words, what moms might be most likely to forget are the bad parts of pregnancy and parenthood in favor of the good. It’s nature’s way of stacking the deck so that we’ll forget the trials and tribulations of pregnancy and parenthood, making it more likely that we will turn around and do it all over again.

The moral of the story is, if you’re having “mom brain,” take heart in knowing that we’ve all been there, and there’s some evidence from neuroscience that it’s not only normal, but may even be beneficial. We can’t of course blame our brains completely—there’s probably a big part of “mom brain” that just comes with being overwhelmed by the new and challenging responsibilities of parenting that invade the same space where our old responsibilities still reside. That means that we may never return to our pre-mom brains, but our new brains—the forgetfulness and emotionality and all—might end up helping us on the way to becoming good, responsive parents.